Field of the Invention
The present invention relates to an input apparatus, an input method and a program. More specifically, the present invention relates to an input apparatus, an input method and a program to control input candidates based on pressing operation against a displayed virtual key.
Description of the Related Art
A hardware keyboard to input characters is frequently mounted on a personal digital assistant such as a cellular phone and a smart phone, and a remote control device for a personal computer, a car navigation system and the like. Hardware keyboards are classified into a type having single selection information allocated to one key as a normal QWERTY keyboard (hereinafter, called a keyboard of a single selection type) and a type having plural selection information allocated to one key as a numerical keypad to perform Japanese character inputting or alphabetical character inputting (hereinafter, called a keyboard of a plural selection type).
In recent years, devices to perform character inputting as displaying a software keyboard on a display screen instead of a hardware keyboard eliminated from the devices targeting miniaturization, cost reduction, ruggedization and design enhancement of the devices are becoming popular. In such cases, a touch panel or a touch-pad to detect touch-input or pen-input of an operator onto the display screen is frequently arranged at the devices. For example, as illustrated in FIG. 1, in the case of operating a software keyboard 18 of a plural selection type, an operator is required to continuously tap a display screen to switch a selection state of one virtual key 18b such as the order of “A”, “B” and “C”. With continuous pressing by tapping, input operation is controlled by detecting contact and non-contact to the display screen. Accordingly, with the continuous pressing utilizing a software keyboard, the operator is required to get his/her finger separated every time from the display screen. When a hardware keyboard is utilized, an operator can perform continuous pressing as maintaining his/her finger contacted to a key. Therefore, input operation with a software keyboard puts a heavier burden on an operator and is more difficult to be performed rapidly compared to a case with a hardware keyboard.
Further, in the case that characters allocated to the same virtual key 18c are continuously input as “E” and “E”, it is required to perform determination operation with another determination button for proceeding to the next input after selecting the first character by tapping. Therefore, inputting is not efficiently performed.
Further, also in the case to vary a state of selected characters such as transform of “KA” to “GA” and “a” to “A”, it is required to press a separately-arranged transform button and the like. This requirement causes decrease in input efficiency. Two issues described above have been common issues during operation of a hardware keyboard of the plural selection type in the related art.
In addition, since tactual feedback may not be obtained with a software keyboard utilizing a touch panel or a touch-pad compared to operation with a hardware keyboard, there has been an issue that typing errors increase.
To address the issues, there has been proposed a method to detect press pressure applied to a virtual key of a software keyboard by utilizing a pressure-sensitive sensor as mounting the pressure-sensitive sensor on a device and to perform key inputting while obtaining tactual feedback by utilizing the press pressure (for example, see Japanese Patent Application Laid-Open No. 11-119882). With the operation method disclosed in Japanese Patent Application Laid-Open No. 11-119882, only kana characters on the top line of the Japanese syllabary (“A”, “KA”, “SA”, “TA”, “NA”, “HA”, “MA”, “YA”, “RA”, “WA”) are allocated respectively to a virtual key. When a specific character (for example, “NA”) is touched from the top line kana characters, grouped kana characters (for example, “NA”, “NI”, “NU”, “NE”, “NO”) belonging to the top line kana character of the touched virtual key are displayed. In Japanese Patent Application Laid-Open No. 11-119882, pressure threshold values are arranged stepwise to select each of the grouped kana characters and press pressure of the virtual key by an operational body is compared to the pressure threshold values arranged stepwise, so that any of the grouped kana characters belonging to the touched virtual key is selected. In this manner, the movement amount of a hand and a sight line of an operator can be reduced during inputting.